Apparatus for evaporating explosive mixtures.



F. I. DU PONT.

APPARATUS FOR EVAPORATING EXPLOSIVE MIXTURES.

APPLICATION FILED NOV. 18, 1908.

2 SHEETS-SHEET 1.

Patented Jan.4, 1910.

WITNESSES: {f W44) P. I. DU PONT. APPARATUS FOR EVAPORATING EXPLOSIVE MIXTURES.

APPLIUATION FILED NOV. 18. 1968. 945,1 O9.

Patented J an. 4, 1910.

2 SHEETS-SHEET 2.

II //////A// M mp N M my Q UNITED STATES PATENT OFFICE.

FRANCIS I. DU FONT, 0F WILMINGTON, DELAWARE, ASSIGNOR TO THE E. I. DU PONT DE NEMOURS POWDER COMPANY, OF WILMINGTON, DELAWARE, A CORPORATION OF NEW JERSEY. 7

APPARATUS FOR EVAPORATIN G EXPLOSIVE MIXTURES.

Improvement in Apparatus for Evaporating Explosive Mixtures, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings, which form a part-of this specification.

My invention has for its object to provide an evaporating apparatus for explosive -mixtures into the evaporator proper of which the explosive mixture is fed in measured and regular quantities and in which the evaporation is uniform through- 5 nected an outlet.

compounding apparatus, has an independent out the mass and all the material worked during such evaporation.

Speaking generally, I employ a plurality of tubes in each of which is a conveying screw, the blades of which'approach closely the inner periphery of the tube. Surround ing each of these tubes is a tube having a header at each end. To one header is connected a passa e for heat supply, say steam or hot air, and to the other header is con- To the interior of each of the conveyer tubes is connected a passage from a pump section or one section of a multiple pump. Each of the screw conveyers has, at one end, a gear which meshes with a gear upon a vertical shaft. The

screw conveyers are revolved at such a high rate of speed that the centrifugal force pro- .duced is such as to throw off any solid particles of the explosive mixture, tending to attach to the blades, to the inner periphery of the tube. A passage in which the explosive mixture passes from the mixing or connection to each pump section and each pump section feeds to a separate evaporating tube.

By this arrangement the explosive mixture'is divided evenly and properly betweenthectubes and all the solid particles are forced and held against the heated periphery while passing through the tube and, in their passage through the tubes, are worked by the conveyer. Thus all portions *of'the mixture are subjected to like heat and Specification of Letters Patent.

Application filed November 18, 1908. Serial No. 463,249.

' Patented Jan. 4, 1910.

are held away from the central moisture of the tube and are equally and in like manner worked during said passage.

I do not claim herein the method consisting in subject-ing the material passing through the evaporatin tube to the action of centrifugal force suIlicient to drive the solid particles to the inner periphery of the evaporating tube and heat and carry the particles along the said inner eriphery to the outlet of the tube with a rubbing action against said tube as the same forms the subject matter of a separate application filed contemporaneously therewith.

I will now describe an embodiment of my invention illustrated in the accompanying drawing and then point out the invention in the claims.

In the drawings: Figure l is an elevation of the apparatus embodying my invention. Fig. 2 is a detail sectional view on line 22 Fig. 1. Fig. 3 is a detail view of a portion of the pump partially broken away. Fig. 4 is a cross section on line M, Fig. 3. Fig. 5 is a perspective view of a pair of pump blades.

a to a are tubes having at one end the header 6 and at the other end the header 0. The header 1) has the inlet pipe at leading from a heat supply, steam or hot air. The header 0 has the outlet pipe 6. Within each tube a to a is a tube, these tubes being respectively lettered f to f. Within each tube f to f is a conveyer g, the blades of which rotate closely to the inner periphery of the tubes f to f. Each conveyer shaft has connected with it a gear h which meshes with a gear 2' on the vertical shaft j. This shaft j is rotated, by means not shown, at a high rate of speed. Each tube f to f has a conduit or pipe entering therein, these being lettered is to k. These pipes is to is lead from the respective tubes f to f to respective sections Z to Z of a multiple pump. Each section of the multiple pump has an inlet m, said inlets connecting by pipes q with a conduit 8, common to all, leading from the explosive mixer or compounder. Each pump section is formed of the shaft 91 having the central bore a and formed at one end with the female threaded portion 0 and 4 when the other blade t is in at the other end with the male threaded portion Surrounding each shaft section is a casing 1", made in sections to slip over the shaft, provided with a circumferential bore 10 eccentric with respectto the shaft.

2? are the blades of each pump Section (shown in detail Fig. 5) provided with a central cut away portion w. The shaft has two orifices m and 3 cut therein to allow the insertion of the blades 25. The blades 25 make a sliding fit in the orifices in the shafts to allow a sliding movement to follow the eccentricity of the bore 10. One orifice, as shown, 3/ is made sufficiently larger than the other to allow the insertion of one blade osition. The inlet m is placed at one end 0 the eccentric portion and the outlet at the other end.

7 The material fed into the pump enters the cavity formed by the eccentricity and is carried by the rotating blades to the outlet, the blades following the eccentricity by reason of the movement with respect to the shaft before described and loose interlocking of the cut away portions of the blades with each other.

It may readily be seen how the pump sections are assembled. Each shaft section being provided with a male and female screw, may be connected to each other, the casings slipped on and glands a inserted to insure tight bearings for the shaft section, said casings are supported upon the shaft and held from rotation by the pipes q.

One end of the shaft 12. has mounted upon itthe gear 1 which meshes with the gear 2 on the shaft 3. At the other end of the shaft is the gear 4 meshing with a gear on the vertical shaft j. Thus the pump is driven from the same shaft which drives the conveyer screws. The central bore a communicates with the oiler 5, thus enabling all sections of the pump to be oiled from a single point.

In practice I have used conveyer tubes of a diameter of 31}; inches with the pitch of the conveyer screw of 2 inches and the length of such tubes 23 feet. The conveyers should rotate at least 288 revolutions, and not below 250 revolutions, per minute. I prefer to rotate them at 300 revolutions per minute.

I have used an explosive mixture comprising 73 per cent. nitrate of soda, 11 per cent. sulfur and 16 per cent. charcoal. These ingredients are mixed, before the evaporation, with equal weight of water, that is to say, to each pound of this mixture is added a pound of water, so that in weight the resultant is 50 per cent. of the explosive and 50 per cent. of the water. After passing through the evaporator, the resultant contains from 10 per cent. to 15 per cent. of water and from 90 to 85 per cent. of powder, the relative percentages of the ingredients of the explosive powder remaining the same as they were initially.

Each of the seven units of the pump should be of sufficient size, when the pump is operated about one hundred revolutions per minute, that each unit delivers about 200 lbs. of the mixture 'per hour. The seven tubes thus deliver an amount of the explosive sufficient to make about 700 lbs. of

powder per hour.

The explosive mixture after treatment in the evaporator falls upon the conveyer c which will carry it to a drier.

In my apparatus, as may be seen during evaporation, instead of carrying the entire volume of the mixture through a series of evaporating tubes, it is divided up and each division carried through a single tube, thus making the result more certain, better and more rapid. Further, all the material is forced to the inner surface of the evaporating tube, thus insuring it receiving like treatment of heat and rubbing and workin I do not herein claim the multisectional pump herein described, as such forms the subject-matter of claims of an application Serial Number 472,808, filed by me January 18th, 1909, a division of this application.

Having now fully described my invention, what I claim and desire to protect by Letters Patent is:

1. In an apparatus for evaporating explosive mixtures, in combination, a conduit adapted to carry the explosive mixture, a plurality of evaporating tubes, a conveyer in each tube, means to heat the walls of said tubes, and means to deliver like quantities of the explosive mixture from the explosive mixture conduit to each evaporating tube.

2. In an apparatus for evaporatingexplosive mixtures, in combination, a conduit adapted to carry the explosive mixture, a

plurality of evaporating tub-es, a conveyer in each tube, a chamber surrounding each tube adapted to receive a heating medium, and an independent pipe from the explosive mixture conduit to each evaporating tube.

3. In an apparatus for evaporating explosive mixtures, in combination, a conduit adapted to carry the explosive mixture, a plurality of evaporating tubes, ;a multisectional pump having sections equal in number to the evaporating tubes, an independent inlet from the explosive mixture conduit to each section of the pump, and an outlet from each section of the pump to its corresponding evaporating tube.

1. In an apparatus for evaporating explosive mixtures, in combination, a conduit adapted to carry the explosive mixture, a plurality of evaporating tubes, a conveying screw in each evaporating tube, a chamber adapted to receive a heating medium surrounding each evaporating tube, a multioutlet from each section of the pump to its sectional pump having sections equal in hereunto set my hand, at Wilmington, Del. number to the evaporating tubes, an indeon this 16th day of Noi'ember 1908. pendent inlet from the explosive mixture FRANCIS I. DU PONT. conduit to each section of the pump and an WVitnesses:

\VM. STANIAR,

corresponding evaporating tube. GORDON L. NAYLOR.

In testimony of which invention, I have 

